JP2966947B2 - Vehicle control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle having a pressing drive member capable of pressing and releasing a pressed drive member.

[0002]

2. Description of the Related Art Conventionally, a pressing drive member and a pressed driving member are provided for various kinds of operation adjustment, switching, and the like, and pressing and pressing of the pressing drive member against the pressed driving member according to an operation state or the like. In some cases, the operating state of the pressed driven member is changed by performing the release. For example, Japanese Patent Application Laid-Open No. 63-162910 discloses a valve timing adjusting device including an advancing ring as a member to be pressed and a retarder as a pressing member capable of pressing and releasing the ring. ing. The device comprises a hub member mounted on a camshaft,
An advancing member that is movable within a certain range in the axial direction is connected to the rotation input member that is linked to the crankshaft, and the hub member and the rotation input member move relative to each other as the advancing member moves in the axial direction. The advancing member and an advancing ring located inside the advancing member are provided with threaded portions and screwed to each other. It has a structure in which a rotating retarder is arranged. When the retarder is pressed against the advancing ring by energization or the like, a braking force due to friction acts on the advancing ring,
The advancing ring is displaced by a predetermined rotation angle with respect to the rotation input member and the advancing member, and the advancing member moves in the axial direction accordingly, so that the rotation phase of the camshaft with respect to the rotation input member changes. Has become.

[0003]

In this type of device, when the pressing drive member (retarder) is pressed against the pressed driving member (advancing ring), the two slide with each other while a braking force is applied. Conventionally, lubricating oil has been supplied between facing portions of both members in order to prevent abrasion and seizure. When the oil is supplied in this manner, the friction coefficient of the contact surface becomes smaller than when no oil is supplied. However, the pressing drive member is usually operated so that a required braking force is applied even in such an oil supply state. Is set.

However, for example, when a pressing drive member is formed by an electromagnetic coil, when the starter is driven, for example, when the engine is started, the battery voltage decreases and the power applied to the electromagnetic coil decreases, so that the pressing force is reduced. May be smaller. Immediately after the switching operation of the pressing drive member from the pressing release state to the pressing state, there is a period in which the pressing force becomes small due to a response delay or the like, and this period may become long due to a temporal change or the like. When the pressing force is reduced in the oil supply state, the braking force (frictional force) on the pressed driven member is insufficient, so that the pressed driven member is not at a correct position when pressed, and therefore,
In the case of a valve timing adjusting device, there is a problem that the valve timing is shifted.

The present invention solves the above-mentioned problem, and prevents the frictional force between the two members from being reduced even when the pressing force of the pressing drive member against the pressed drive member is reduced. It is an object of the present invention to provide a control device for a vehicle that can appropriately adjust the operation state of a pressing drive member and can prevent a deviation in valve timing when applied to adjustment of valve timing.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the present invention is incorporated in a variable valve timing mechanism between a camshaft and a rotary input member for the camshaft.
A pressed drive member that is displaced when pressed to change the phase of the camshaft with respect to the rotary input member, and that can be pressed and released from the pressed drive member and is electromagnetically actuated A driving member, pressing force applying means for applying a pressing force formed by an electromagnetic force to the pressing driving member to the pressing driving member, means for supplying oil between the pressing driving member and the pressed driving member, Determining means for determining a state in which the pressing force is small at the time of pressing operation; and, when the determining means determines that the state in which the pressing force is small, the oil is supplied between the pressing drive member and the pressed drive member by the oil supply means. Limiting means for restricting the supply, wherein the determining means adjusts when the battery voltage decreases as the pressing force is reduced and when the pressing drive member switches to the pressing operation state. The limiting means limits the oil supply for a first set time when the battery voltage is lowered, and for a second set time from the start of the pressing operation when the pressing drive member switches to the pressing operation state. The second set time is set to be longer than the first set time.

[0007]

According to the above construction, when the pressing force of the pressing drive member against the pressed drive member decreases, the oil supply is restricted, so that the friction coefficient of the contact surface between the two members increases. The decrease in the pressing force is compensated for by the increase in the friction coefficient, and the decrease in the frictional force between the two members is prevented.

[0008] By preventing the reduction of the frictional force, an appropriate valve timing adjustment operation is ensured in the variable valve timing mechanism in which the above-mentioned pressed drive member is incorporated.

Further, the oil supply is restricted when the battery voltage is reduced as the pressing force is small or when the pressing drive member is switched to the pressing operation state, and the time for limiting the oil supply is appropriately set accordingly. It is adjusted to.

[0010]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a case where the present invention is applied to an apparatus for controlling valve timing as an embodiment of the present invention. In this figure, reference numeral 1 denotes a camshaft, which is rotatably supported on a cylinder head 2. Reference numeral 3 denotes a gear as a rotation input unit, which is arranged around an end of the camshaft 1. The gear 3 receives the rotation transmitted from the crankshaft of the engine. For example, as shown in FIG. 2, an intake camshaft 1 and an exhaust camshaft 1 'are arranged on a cylinder head, and A cam pulley 4 provided at an end of the side camshaft 1 'and a crank pulley (not shown) are connected by a timing belt, and gears 3, 3' provided on each camshaft 1, 1 '.
The rotation from the crankshaft is input to the gear 3 of the intake-side camshaft 1 via the cam pulley 4 and the gear 3 'of the exhaust-side camshaft 1'.

[0011] Between the camshaft 1 and the gear 3,
A variable valve timing mechanism 5 as shown in FIG. 1 is provided. The variable valve timing mechanism 5 changes a valve timing (opening / closing timing of an intake valve) by changing a rotation phase of the camshaft 1 with respect to the gear 3, and includes a hub 6, a ring-shaped advancing plate 7, and a drum 8. , An electromagnetic coil 9 and the like.

The hub 6 is fixed to the camshaft 1, and a helical claw 6a is formed on the hub 6 so as to project therefrom. The advancing plate 7 is formed by a helical gear formed on the outer periphery of the advancing plate 7.
0 and is spline-coupled to the inner peripheral surface of the gear 3. Thus, the rotation of the gear 3 is transmitted to the hub 6 and the camshaft 1 via the advancing plate 7.

The inner peripheral surface of the advancing plate 7 and the outer peripheral portion of the drum 8 have corresponding thread-shaped irregularities 1.
1 and 12 are formed, and both are screwed together. The drum 8 is connected to the hub 6 via a return spring 13. Further, between the hub 6 and the drum 8,
A stop plate 14 for limiting the rotation angle of the drum 8 with respect to the hub 6 is provided.

The electromagnetic coil 9 is connected to a battery 16
And a holder 9b for holding the coil 9a. The end of the holder 9b faces the end surface of the drum 8 so that it does not rotate with respect to the cylinder head 2 but can move in the axial direction. Is attached via a mounting member 15. In this embodiment, the drum 8 corresponds to a pressed drive member, and the electromagnetic coil 9 corresponds to a press drive member. When the electromagnetic coil 9 is excited, the drum 8 is pressed, and when demagnetized, it is released. .

When the electromagnetic coil 9 is in the released state, the rotation of the hub 6 is transmitted to the drum 8, and the gear 3, the advancing plate 7, the drum 8, the hub 6, and the camshaft 1 are moved to a fixed position. However, when the electromagnetic coil 9 is excited to be in a pressed state, a braking force is applied to the drum 8, whereby the drum 8 rotates relative to the gear 3 and the advancing plate 7, and the stop plate 14 It is displaced by a regulated predetermined rotation angle. Accordingly, the advancing plate 7 moves in the axial direction by a fixed amount.
The relative rotation of the hub 6 connected to the gear 3 via the helical gear causes the camshaft 1 relative to the gear 3 to move.
Is changed.

A switching circuit 17 is provided between the electromagnetic coil 9 and the battery 16 for switching between an energized state by energizing the electromagnetic coil 9 and a demagnetized state by stopping energization. A pressing force applying means for generating a pressing force by energizing the electromagnetic coil 9 is constituted by the circuit for use.

The cylinder head 2 is provided with an oil passage 20 through which oil supplied by an oil pump (not shown) is introduced. From this oil passage 20, a passage 21 for supplying oil to a camshaft bearing is formed. And a passage 22 for supplying oil to the variable valve timing mechanism 5 are branched. The oil passing through the passage 22 is supplied to the camshaft 1
An oil sump space 23 outside the end, a passage 24 formed in the camshaft 1, a gap 26 between the camshaft 1 and a camshaft bolt 25 therein, and a passage 27 formed in the camshaft 1. , Into the space inside the electromagnetic coil 9. The passage 22, the space 23, the passage 24, the gap 26, and the passage 27 form the electromagnetic coil 9.
Oil supply means for supplying oil is provided between the (pressing drive member) and the drum 8 (pressed drive member).
Further, a solenoid valve 28 that opens and closes in response to a control signal is provided in the passage 22.

Reference numeral 30 denotes a control unit (ECU) for controlling the variable valve timing mechanism 5 and the oil supply means, and comprises a microcomputer or the like. The control unit 30 receives an engine speed detection signal from an engine speed sensor 31, an intake air amount detection signal from an air flow meter 32 provided in an intake passage of the engine, a battery voltage signal from the battery 16, and the like. , This control unit 30
Thus, control signals are output to the switching circuit 17 and the solenoid valve 28, respectively.

The control unit 30 constitutes a valve timing control means 33 and determines a state in which the pressing force is small when the electromagnetic coil 9 is pressed, and a state in which the determining means 34 determines that the pressing force is small. And a restricting means 35 for restricting the oil supply between the electromagnetic coil 9 and the drum 8 by the oil supply means when the determination is made.

The valve timing control means 33 turns on (energizes) the electromagnetic coil 9 according to the operating state based on the setting of the operating state based on the engine speed and charging efficiency (the amount of intake air per engine revolution). ),
It controls off (stop of power supply). In this embodiment, as shown in FIG. 3, when the electromagnetic coil 9 is off, the timing is relatively late (broken line), and when the electromagnetic coil 9 is on, the timing is advanced and the timing is relatively early (broken line). While the variable valve timing mechanism 5 is configured, an area is set in the control unit 30 as shown in FIG. That is, in the low speed region including the starting region, the electromagnetic coil 9 is turned on to advance the valve timing to prevent the blow-back of the intake air, etc. The electromagnetic coil 9 is turned off to increase the number.

As will be described later, the determination means 34 determines whether the battery voltage drops at the time of starting the engine or the like and when the switching to the electromagnetic coil 9 is on, as will be described later. . The limiting means 35 closes the solenoid valve 28 for a predetermined time from the start of the operation of turning on the electromagnetic coil 9 at the time of the battery voltage drop or the switching transition.

A specific example of the processing performed by the control unit 30 as the judging means 34 and the limiting means 35 is as follows.
This is shown in the flowchart of FIG. Note that the processing as the valve timing control means 33 is performed by another routine, and this processing is well known in the related art and will not be described.

When the process shown in FIG. 5 starts, the control unit firstly proceeds to step S1 to determine the engine speed NE.
, The battery voltage VB, and the intake charging efficiency CE, which is the amount of intake air per one revolution of the engine, are read.
At 2, it is determined whether or not the electromagnetic coil on switch KVC is "1". The switch KVC is set to “1” in a region where the electromagnetic coil 9 is turned on and “0” in a region where the electromagnetic coil 9 is turned off based on the region setting shown in FIG. " If the determination in step S2 is NO, the process returns as it is, and the processing from step S1 is repeated.

When the determination in step S2 is YES, that is, when the electromagnetic coil 9 is on, it is determined in step S3 whether or not the battery voltage VB has dropped below the set value CVB. When starting the engine, the battery voltage V
If B has fallen below the set value CVB, the solenoid valve 28 of the oil supply means is closed in step S4. Then, a time T1 from the start of the operation of turning on the electromagnetic coil is checked (step S5). The solenoid valve 28 is kept closed until the time T1 reaches the set time A, and when the set time A has elapsed, the solenoid valve 28 is turned off. Leave open.

When the determination in step S3 is NO (when the battery voltage has not dropped), it is determined in step S7 whether or not the variable valve timing mechanism operation flag XVC is "0". The flag XVC indicates whether or not the valve timing has actually been changed after the electromagnetic coil is turned on, based on, for example, detection of the movement of the advancing plate 7, and the valve timing has not been actually changed. The interval is "0", and after the actual operation, it is "1".

When the flag XVC is "0", a time T2 from the time when the electromagnetic coil is turned on is checked (step S8). If the time T2 is less than the set time B, the solenoid valve 28 is closed. (Step S
9). Then, while the flag XVC is “0” and the set time B has not been reached, steps S7 to S9 are repeated to maintain the closed state of the solenoid valve 28. When the set time B has elapsed, the process proceeds to step S6, and when the flag XVC becomes "1" due to the fact that the valve timing is actually changed, the process proceeds to step S6.
Then, the solenoid valve 28 is opened.

According to the apparatus of this embodiment as described above, the electromagnetic coil 9 is turned on and off according to the operating state of the engine. When it is turned on, the valve timing is advanced by the drum 8 being brought into a predetermined rotational displacement state by the braking force of the electromagnetic coil 9 as described above, and when the electromagnetic coil 9 is turned off. With the release of the pressing force, the drum 8 is returned to the original relative position with respect to the gear 3 by the action of the return spring 13. on the other hand,
The solenoid valve 28 of the oil supply means is normally opened, and oil is supplied between the drum 8 and the electromagnetic coil 9 to prevent wear and influence.

By the way, when the engine is started, power is consumed by the operation of the starter and the battery voltage may drop to a set value or less. If such a drop in the battery voltage occurs, the operation shown in FIG. In the processing in steps S4 to S6 based on the determination in step S3, the solenoid valve 28 is closed for the set time A and the oil supply is stopped, so that an appropriate valve timing adjustment operation is ensured. In other words, when the battery voltage is low, the pressing force of the electromagnetic coil 9 is small. If the oil supply is performed at this time, the braking force is insufficient and the drum does not enter the predetermined rotational displacement state, and the valve timing is sufficiently advanced. And the combustion stability is impaired. On the other hand, if the oil supply is stopped when the battery voltage drops as in the present embodiment, the frictional coefficient between the contact surface between the drum 8 and the electromagnetic coil 9 increases, thereby compensating for the decrease in the pressing force and the drum 8. As a result, a braking force required to bring the vehicle into a predetermined rotational displacement state is obtained, and the valve timing is properly adjusted.

When the electromagnetic coil 9 is switched from off to on in response to a change in the operating state during normal operation, the drum 8 is switched immediately after the switching due to a response delay or the like.
When the oil is supplied, the pressing force of the electromagnetic coil 9 is small, and the braking force is likely to be insufficient. Also in such a case, the oil supply is stopped for the set time B in steps S7 to S9 in FIG.
The braking force is increased, the rotational displacement of the drum 8 is promoted, and the valve timing is changed quickly.

In these cases, if the suspension of the oil supply lasts for a long time, abrasion and heat generation are liable to occur.
Since the pressing operation is in the initial stage, the stop of the oil supply is
Only the set times A and B are set from the start of the pressing operation when the electromagnetic coil 9 is turned on.

In setting the times A and B, it is desirable that A <B in consideration of the following points. That is, since the amount of oil between the drum 8 and the electromagnetic coil 9 is small from the beginning when the engine is started, the oil supply stop time A
The friction coefficient is sufficiently increased even if the length is short, but when the electromagnetic coil is switched on during the operation of the engine, a considerable amount of oil remains between the drum 8 and the electromagnetic coil 9 so that the friction coefficient increases. To stop the oil supply time B
Needs to be lengthened to some extent.

In the above embodiment, the oil supply is stopped as a process for restricting the oil supply between the drum 8 and the electromagnetic coil 9 when the pressing force of the electromagnetic coil 9 is small. May be reduced.
In addition, the specific structure of each part may be variously changed without departing from the gist of the present invention.

[0033]

According to the vehicle control apparatus of the present invention, oil is supplied between the pressing drive member and the pressed driving member by the oil supply means, and the oil is supplied when the pressing drive member is pressed. When the state in which the pressure is small is determined by the determining means, the restricting means restricts the oil supply between the pressing drive member and the pressed driven member by the oil supply means. Is reduced, the reduction in the frictional force is suppressed, and the operating state of the pressed drive member can be properly adjusted. Then, by appropriately adjusting the operating state of the pressed drive member incorporated in the variable valve timing mechanism, it is possible to prevent the valve timing from shifting even when the pressing force is reduced.

In particular, when the pressing force decreases due to a decrease in the battery voltage, by restricting the oil supply, it is possible to prevent the occurrence of a deviation in valve timing and the like. Even at the time of switching to the state, by restricting the oil supply, it is possible to satisfactorily change the valve timing at the time of the switching. Further, the oil supply is limited only for a first set time when the battery voltage is low, and for a second set time when the switching is performed,
In addition, since the second set time is set longer than the first set time, the time for restricting the oil supply is appropriately adjusted according to each, and the adjustment of the valve timing and the like are effectively performed. In this way, it is possible to sufficiently prevent wear and heat generation of the two members.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of an apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory plan view of a pair of camshafts.

FIG. 3 is a diagram showing valve timing of intake and exhaust valves.

FIG. 4 is a diagram showing an area setting for switching a valve timing according to an operation state.

FIG. 5 is a flowchart illustrating a specific example of a process performed by a control unit as a determining unit and a limiting unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camshaft 3 Gear 5 Variable valve timing mechanism 8 Drum 9 Electromagnetic coil 22 Passage of oil supply means 28 Solenoid valve 30 Control unit 34 Judgment means 35 Limiting means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01L 1/34 F02D 13/02 F16D 27/14

Claims (1)

(57) [Claims] 1. A camshaft and a rotation input unit for the camshaft
Built into the variable valve timing mechanism between the material
Displaced when pressed, camshaft against rotary input member
A pressed drive member that changes the phase of the shaft;
It is possible to press and release the pressure
Te, a press drive member actuated electromagnetically, electrostatic by energizing
Pressing force applying means for applying a pressing force consisting of a magnetic force to the pressing drive member, means for supplying oil between the pressing drive member and the pressed drive member, and a small pressing force when the pressing drive member is pressed. Determining means for determining a state, and limiting means for limiting oil supply between the pressing drive member and the pressed driving member by the oil supply means when the pressing force is determined to be small by the determining means. And the determination means determines that the pressing force is small and the battery
When the re-voltage drops and the pressing operation of the pressing drive member
The switching means is checked at the time of switching to
When the pressure decreases, the pressure
When the moving member switches to the pressing operation state,
The oil supply is restricted for the second set time from the start of operation
And the second set time is equal to the first set time.
A control device for a vehicle, wherein the control time is set to be longer than a set time .